In this work, a preliminary study was conducted to study the effects of different types and concentrations of cosolvents
based on the total yield and antioxidants capacity prior to supercritical fluid extraction (SFE) of Orthosiphon stamineus
(locally referred as misai kucing). Initially, a comparison was made by cold maceration technique with nine types of
different cosolvents, namely water, pure ethanol, 25% (v/v) of ethanol in water, 50% (v/v) of ethanol in water, 75% (v/v) of
ethanol in water, pure methanol, 25% (v/v) of methanol in water, 50% (v/v) of methanol in water and 75% (v/v) of methanol
in water. The antioxidant capacity was analysed by free radical scavenging activity of 2,2-diphenyl-1-picrylhydrazyl
(DPPH), total phenolic content (TPC) and total flavonoid content (TFC). Aqueous ethanolic solvent of 50% (v/v) ethanol in
water showed the highest total yield of extract of 4.64 ± 0.02%. All antioxidant assays of TPC and TFC showed the highest
value of 3.42 ± 0.08 mg GAE g−1 extract, 4.7 ± 0.14 mg CAE g−1 extract, respectively and IC50 value for DPPH was 0.625
µg/mL for 50% (v/v) ethanol in water extract. Based on the overall result, ethanolic solvents gave a better result for all
antioxidant assays compared to those of methanolic solvents. Using the selected cosolvent, the identification of target
compounds, which were rosmarinic acid, eupatorin and sinensetin from supercritical fluid extraction was determined
by using HPLC. In conclusion, ethanol-water solvent was efficient in extracting bioactive compounds in O. stamineus
and also improved the total yield, thus the usage of ethanolic solvent in different concentrations should be considered
for further optimisation of SFE with cosolvent studies.
This study attempts to assess the impact of various types of land use along Sungai Langat and describes hydrological
change and water quality variation along this river. This study also determines water quality of Sungai Langat based on
low flow dry period Q100,7 using the application of QUAL2K. Dissolved oxygen (DO), pH, temperature and conductivity
were measured in situ. Biochemical oxygen demand (BOD5
), ammonia nitrogen (NH3
-N) and total suspended solid (TSS)
were analysed according to the standard methods (APHA). Water quality data was referred to National Water Quality
Standards for Malaysia (NWQS) proposed by Malaysian Department of Environment (DOE) to estimate Sungai Langat
water quality status. Four important water quality parameters namely DO, BOD5, NH3
-N and TSS were simulated with
QUAL2K version 2.07 for 83.67 km. As regard to individual parameter, DO classified this river into class III, BOD5 in
Class II, NH3
-N in Class IV and TSS in Class I. Based on QUAL2K simulation for low flow scenario, the results clearly
demonstrates a gradually reduction of DO and BOD5 whereas NH3
-N and TSS display opposite. Only NH3
-N was found
significantly increase which cause low water quality class towards the downstream. Three parameters namely DO, BOD5
and NH3
-N show effects of industrial which approximately located at the middle of river stretch. The TSS was contributed
to the river system at the upstream and downstream of the river stretch which most likely from sand mining activity which
located at Sungai Long, Cheras (near R5) and Sungai Semenyih (R11).
A study was conducted to investigate the antiviral activity of aqueous extracts from Orthosiphon stamineus (OS).
Extraction was done using different parts of OS. The whole plant except root (WPOS), leaves (LOS) and flowers (FOS) of
OS were extracted using aqueous extraction method. Cytotoxicity was assessed using 3-(4,5-dimethylthiazol-2,5-diphenyl
tetrazolium bromide (MTT) assay. Plaque reduction assays were carried out to evaluate the antiviral activity of OS extract
against herpes simplex virus type 1 (HSV-1). These include post-treatment, pre-treatment and virucidal assays. High
antiviral activity was observed in post-treatment and virucidal assay with 100% reduction of HSV-1 plaque at 0.39 mg/
mL in LOS, FOS and WPOS. In pre-treatment assay, 79%, 84% and 97% plaque reduction using the same concentration
was observed in FOS, LOS and WPOS, respectively. In conclusion, this study showed that OS aqueous extract has promising
potential to be explored as anti-HSV-1 agent regardless of the mode of treatment.
Numerous studies have shown that parasites potentially become bio-accumulators for heavy metals. The heavy metals
content in parasite-infected fish was reported to be lower compared to the parasite non-infected fish. Evaluation of heavy
metal content in Nemipterus peronii and Paraphilometroides nemipteri was performed using ICP-OES. Our result has
shown that arsenic was the most abundance heavy metal content in muscle N. peronii and P. nemipteri, suggesting that
the parasite has the ability to accumulate heavy metals. Heavy metals were reported to induce oxidative stress where
glutathione and p38 protein may be involved. Thus, expression of the p38 protein was determined using western blot
technique and glutathione content was measured fluorometrically. The p38 expression in P. nemipteri of Pulau Kambing
was higher compared to P. nemipteri of Besut has shown that the parasite may exposed to stress. Glutathione content
showed no significant changes due to detoxification mechanism occurred in the parasite. In this study, we could conclude
that P. nemipteri could be a bio-accumulator, whereas p38 protein and glutathione as indicator of stress level in the
parasite that exposed to the heavy metals.
A series of check dams (or small dams in shallow streams) have been placed on many streams throughout Thailand and
the number of them continue to increase. Check dam construction activities have been emphasized by the government
and private sector entities over the last decade to prevent severe flood or drought due to changes in rainfall patterns. This
study evaluated distribution of functional feeding groups (FFG) in a stream with a high density of check dams. Twelve
sampling sites at three altitudes (500, 900 and 1500 m asl) included undammed and nearby dammed sections (above
and below check dams) were used. Aquatic insects were collected monthly at each site for a year and categorized into
FFG. Aquatic insect composition of undammed and above dam sites was different. Abundance within each FFG at above
dam sites significantly differed from undammed sites. Taxonomic richness at 1500 and 900 m altitudes was decreased
at above dam sites compared with the corresponding undammed sites, whereas above dam sites of 500 m altitude had
higher richness than undammed site. High abundance of predators and collector-gatherers associated with reservoirs
and fine sediment accumulation above dams, where filter-feeders were scarce. Shredder abundance varied among sites
and was highest where leaf packs were most abundant. Scrapers were least abundant group and inconsistent with the
dams. Distribution of FFG was similar to changes in other regulated streams. The composition of FFG reflected the
stream ecosystem conditions through adaptation of communities to stream habitat and food resources, including those
associated with check dam construction.
The empty fruit bunches of oil palm have been used as the raw material to produce biofuel. However, the lignin present
in oil palm tissues hampers the enzymatic saccharification of lignocellulosic biomass and lower the yield of biofuel
produced. Hence, various efforts were taken to identify the lignin biosynthetic genes in oil palm and to investigate
their regulation at the molecular level. In this study, a lignin biosynthetic gene, Eg4CL1 and its promoter were isolated
from the oil palm. Eg4CL1 contains the acyl-activating enzyme consensus motif and boxes I & II which are present in
other 4CL homologs. Eg4CL1 was clustered together with known type I 4CL proteins involved in lignin biosynthesis in
other plants. Gene expression analysis showed that Eg4CL1 was expressed abundantly in different organs of oil palm
throughout the course of development, reflecting its involvement in lignin biosynthesis in different organs at all stages
of growth. The presence of the lignification toolbox - AC elements in the 1.5 kb promoter of Eg4CL1 further suggests the
potential role of the gene in lignin biosynthesis in oil palm. Together, these results suggested that Eg4CL1 is a potential
candidate gene involved in lignin biosynthesis in oil palm.
Remote sensing and GIS are robust tools in detection of fishing grounds which is important in providing fish sustainability
for human being. This recent tool allows fishing grounds detection at minimal cost and optimizes effort. The objectives
of this study were to investigate the relationship between R. kanagurta fishing grounds with environmental factors and
to determine its potential fishing grounds. MODIS derived satellite data of Chl-a and sea surface temperature (SST)
and fisheries catch data of 2008 and 2009 were analyzed using suitability index (SI) and generalized additive model
(GAM) in the Exclusive Economic Zone (EEZ) off the East Coast of Peninsular Malaysia. Distribution of R. kanagurta
was associated with preferred range of 0.20 to 0.30 mg/m3 for Chl-a and 29 to 30°C for SST. GAM indicated that these
parameters influenced fish distribution (p<0.001). Potential fishing ground maps derived from the SI and GAM model
indicated accuracy at 75% with kappa of 0.7 and accuracy at 87.6% with kappa of 0.8, respectively. This study indicated
the capability of GAM as an exploratory tool to map the potential fishing grounds of R. kanagurta in the EEZ waters.
China is one of the largest citrus producers in Asia, where Phytophthora parasitica infection has become the major
threat in sustaining long term citrus production. The proposed study examined the effects of P. parasitica on Citrus junos,
C. limon, C. tangerina and Poncirus trifoliata to evaluate the resisted rootstock to Phytophthora root rot. P. parasitica
infection notably decreased plant growth, root morphology and activities of pathogenesis-related proteins (PRs) in
C. limon and C. tangerina. Root β-1,3-glucanase, chitinase and phenylalanine ammonialyase activities significantly
increased in C. junos and P. trifoliata after infection with P. parasitica. P. parasitica infection notably decreased root
salicylic acid concentrations in C. limon, C. tangerina and P. trifoliata, while increasing it in C. junos. An opposite
trend was observed in root jasmonic acid levels after infection with P. parasitica, relative to root salicylic acid. Root
nitric oxide and calmodulin concentrations were significantly increased in P. parasitica-infected C. junos, C. tangerina
and P. trifoliata, while C. limon exhibited a decrease. These results demonstrated that citrus species like C. junos and P.
trifoliata displayed a much higher resistance to Phytophthora-induced root rot, and C. limon and C. tangerina showed
a comparatively lower degree of resistance.
The epoxidation process of RBD palm oil was carried out using in situ generated performic acid. The effect of various
process variables such as the formic acid towards hydrogen peroxide mole ratio, the reaction temperature and the
reaction time were optimized by using response surface methodology (RSM). The D-optimal design was used to evaluate
the influence of process variables and their interaction in order to obtain the process optimum conditions. The results
showed that the optimum conditions of the epoxidation process were at 5.91 mole ratio of formic acid towards 3.60 mole
of hydrogen peroxide, reaction temperature of 40ºC and reaction time of 2.55 h. At the optimum condition, the epoxidised
RBD palm oil (EPO) yield was 86% with oxirane oxygen content (OOC) of 3.46%. The results showed in good agreement
with the predicted values from the RSM model.
Fungi associated with Vaccinium species play important roles in plant growth and disease control, especially in the final
blueberry production. Vaccinium dunalianum var. urophyllum (Ericaceae) is a well-known medicinal plant in Southern
China used to treat inflammation and microbial infections. The endophytic fungi from these plants are therefore anticipated
as potential new sources of antimicrobials. In this report, the inhibitory effects of endophytes against clinical bacteria
and yeast were comprehensively screened and 11 isolates indicated high bioactivity by the agar diffusion method. The
corresponding crude extracts of these fungi under submerged fermentation also demonstrated distinct differences and
n-butyl alcohol displayed the lowest extraction efficiency among the extracts. The ethyl acetate and dichloromethane
extracts of filtrates from the Colletotrichum sp. VD001, Epicoccum nigrum VD021 and E. nigrum VD022 strains
displayed good properties against pathogenic microorganisms according to disc diffusion assays and minimal inhibitory
concentration (MIC). This study is the first indicating that cultivable endophytic fungi associated with blueberry plants
produce potential compounds against clinical pathogens.
LUSI (Lumpur“mud”-Sidoarjo) is the mud volcanic which was initiated by the failed gas drilling exploration activities
carried out near an urban area. The evaluation of the LUSI mud volcanic emission and its dried mud effects on air pollution
and human health was carried out from 2011 to 2012. The concentrations of particulate matter (PM2
.
5
), hazardous
gases (H2
S, SO2
, NO2
), volatile organic compounds (VOC): Including total hydrocarbons (THC)), toluene (C6
H5
CH3
) and
benzene (C6
H6
) as well as heavy metals (Pb, Cr and Cd) were measured following standard methods. The results showed
that the average concentration of PM2.5 ranged from 24.0-399.9 μg/m3
, H2
S: 1.53-2.92 ppm; SO2
: 0.021-1.321 ppm and
NO2
: 0.007-0.076 ppm. The VOC included total hydrocarbons from 0.57-0.96 ppm, toluene 0.33-0.92 ppm and benzene
0.33-0.40 ppm. Furthermore, heavy metal concentrations were as follows: Pb 2.6-37.34 μg/m3
; Cr 0.14-12.8 μg/m3
and
Cd 0.78-4.16 μg/m3
. LUSI contributed to increased air pollution primarily through H2
S, SO2 and PM2.5. The Air Quality
Index (AQI) of PM2.5 (164-217) and SO2
(235-291) showed that the air quality at the disaster area was ‘very unhealthy’.
Backward trajectories indicated that the wind direction may have had an impact on the air pollution load.
Bat surveys at Gunung Gading National Park (GGNP) were conducted for 29 non-consecutive nights, which consisted
of five separate sampling sessions from November 2011 until November 2015. A total of 378 individuals representing
36 species from six families were captured, from an accumulated effort of 435 trapping nights. This corresponds to
approximately 39% (n=36) of the total species recorded in Borneo. The most commonly captured species in GGNP for
insectivorous bats was Rhinolophus affinis (20.1%), whereas for frugivorous bats Penthetor lucasi (14.3%) dominated the
capture. Species accumulation curve reached asymptote on the 24th sampling night suggesting that sampling saturation
has been achieved for the trapping sites studied here. The species diversity (H’= 2.75) showed relatively high diversity
of bat species in the park compared to other actively surveyed sites in western Sarawak including Bako National Park
(Bako NP), Kubah National Park (Kubah NP) and Mount Penrisen (Mt Penrisen). This was further supported through
rarefaction analysis showing that GGNP has largest value of estimated species compared to other actively surveyed
sites in western Sarawak. Lunar phase and bat capture rate correlation analysis showed that there is no statistically
significant relationship between lunar phase and the bat capture rate at GGNP. This suggests that bat activity reported
here were not affected by moonlight. The results from these surveys provided the most comprehensive list of bats for
GGNP. Our study highlights the importance of GGNP as an important habitat for bat conservation including the rare bat
species found in Borneo, Phoniscus atrox.
Despite the increasing numbers of hydrodam worldwide, only a handful of studies evaluated their impacts on biodiversity.
Compared to terrestrial animals, birds were thought to be less affected by inundation process, following impoundment. At
the Hulu Terengganu Hydroelectric Dam in Peninsular Malaysia, our study compared species assemblages and diversity
of birds within the dam area (i.e. the dam reservoir and catchment area) after recent logging and inundation in relation
to a nearby forest logged 30 years ago. Using point count and mist-netting techniques, we recorded a total of 64 species
(Shannon Index (H’) = 3.827) in the dam area and 91 species (H’=3.99) in historically-logged forests. Insectivore species
richness was significantly higher in the historically-logged forests (Mann-Whitney: Z=4.339, N=205, p<0.005). These
results indicated that richness and diversity of bird species assemblages appear to decline following recent inundation
phase. Nevertheless, the forests in the dam area still harbour charismatic species such as eagles (Family: Accipitridae)
and hornbills (Family: Bucerotidae) which suggests that this habitat is relatively important for birds.
The purpose of this study was to examine the effect of viscous dissipation on mixed convection flow of viscoelastic
nanofluid past a horizontal circular cylinder. Carboxymethyl cellulose solution (CMC) is chosen as the base fluid and
copper as a nanoparticle with the Prandtl number Pr = 6.2. The transformed boundary layer equations for momentum
and temperature subject to the appropriate boundary conditions are solved numerically by using Keller-box method. The
influenced of the dimensionless parameters such as Eckert number, mixed convection parameter, nanoparticles volume
fraction and viscoelastic parameter on the flow and heat transfer characteristics is analyzed in detail and presented
graphically. The results come out with the velocity profiles are increased while the temperature profiles are decreased
by increasing the values of nanoparticles volume fraction and viscoelastic parameter, respectively. The graph shows
that, increasing Eckert number the skin friction is also increases. The values of skin friction are increased by increasing
mixed convection parameter, but the values of Nusselt number produce an opposite behavior. The present study has many
applications especially in heat exchangers technology and oceanography. Therefore, in future, it is hoping to study the
viscoelastic nanofluid flow past a different geometric such as sphere and cylindrical cone.
The growing number of multi-population mortality models in the recent years signifies the mortality improvement in
developed countries. In this case, there exists a narrowing gap of sex-differential in life expectancy between populations;
hence multi-population mortality models are designed to assimilate the correlation between populations. The present
study considers two extensions of the single-population Lee-Carter model, namely the independent model and augmented
common factor model. The independent model incorporates the information between male and female separately
whereas the augmented common factor model incorporates the information between male and female simultaneously.
The methods are demonstrated in two perspectives: First is by applying them to Malaysian mortality data and second
is by comparing the significance of the methods to the annuity pricing. The performances of the two methods are then
compared in which has been found that the augmented common factor model is more superior in terms of historical fit,
forecast performance, and annuity pricing.
MeSH terms: Biological Phenomena; Female; Forecasting; Life Expectancy; Male; Life Tables; Developed Countries
This paper delves into the problem of mixed convection boundary layer flow from a horizontal circular cylinder filled in
a Jeffrey fluid with viscous dissipation effect. Both cases of cooled and heated cylinders are discussed. The governing
equations which have been converted into a dimensionless form using the appropriate non-dimensional variables are solved
numerically through the Keller-box method. A comparative study is performed and authentication of the present results
with documented outcomes from formerly published works is excellently achieved. Tabular and graphical representations
of the numerical results are executed for the specified distributions, considering the mixed convection parameter, Jeffrey
fluid parameters and the Prandtl and Eckert numbers. Interestingly, boundary layer separation for mixed convection
parameter happens for some positive (assisting flow) and negative (opposing flow) values. Strong assisting flow means
the cylinder is heated, which causes the delay in boundary layer separation, whereas strong opposing flow means the
cylinder is cooled, which conveys the separation point close to the lower stagnation point. Contradictory behaviours
of both Jeffrey fluid parameters are observed over the velocity and temperature profiles together with the skin friction
coefficient and Nusselt number. The increase of the Prandtl number leads to the decrement of the temperature profile,
while the increase of the Eckert number results in the slight increment of the skin friction coefficient and decrement of
the Nusselt number. Both velocity and temperature profiles of Eckert number show no effects at the lower stagnation
point of the cylinder.
A cylindrical data set consists of circular and linear variables. We focus on developing an outlier detection procedure
for cylindrical regression model proposed by Johnson and Wehrly (1978) based on the k-nearest neighbour approach.
The procedure is applied based on the residuals where the distance between two residuals is measured by the Euclidean
distance. This procedure can be used to detect single or multiple outliers. Cut-off points of the test statistic are generated
and its performance is then evaluated via simulation. For illustration, we apply the test on the wind data set obtained
from the Malaysian Meteorological Department.
This study analyzes the heat transfer of a thin film flow on an unsteady stretching sheet in nanofluids. Three different types of nanoparticles are considered; copper Cu, alumina Al2O3 and titania TiO2 with water as the base fluid. The governing equations are simplified using similarity transformations. The resulting coupled nonlinear differential equations are solved by the Homotopy Analysis Method (HAM). The analytical series solutions are presented and the numerical results obtained are tabulated. In particular, it shows that the heat transfer rate decreases when nanoparticles volume fraction increases.
Chitosan/polyvinyl alcohol (Chitosan/PVA) blended film was prepared by direct blend process and solution casting methods.
In order to reduce the swelling ratio and enhance the chemical and mechanical stability, Chitosan/PVA film was crosslinked
with glutaraldehyde in order to produce Chitosan-g-PVA. Bovine serum albumin (BSA) was used as a model protein
to incorporate into the Chitosan-g-PVA. The chemical structure and morphological characteristics of films were studied
by FT-IR and scanning electron microscopy (SEM). Mechanical and physical properties of blended films such as tensile
properties in the dry and wet states, water uptake and water contact angle measurement were characterized. Blending
PVA and chitosan improved strength and flexibility of the films. Crosslinking with glutaraldehyde further improves the
tensile strength and decrease the hydrophilicity of films. BSA immobilized on the Chitosan-g-PVA film was calculated as
BSA encapsulation efficiency.
This study aimed to improve the colloidal stability of yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP)
suspension through colloidal processing to obtain highly translucent Y-TZP. Agglomeration is often the main complication
in the processing of nanosized Y-TZP as it deteriorates mechanical and optical properties. Thus, colloidal processing
is necessary to mitigate the agglomeration in Y-TZP. The colloidal stability of Y-TZP suspension plays a key role for the
success of colloidal processing. In this study, colloidal processing was conducted at several stages, namely, dispersant
addition, pH adjustment and sedimentation. Changes in particle size and zeta potential at various stages were recorded.
The suspensions were then slip-casted to form green bodies. Green bodies were sintered and characterized for density
and translucency. The results showed that dispersant addition followed by pH adjustment effectively dispersed soft
agglomerates by introducing electrosteric stabilization, whereas sedimentation successfully segregated hard agglomerates
and contributed excellent colloidal stability. With high colloidal stability, the translucency of Y-TZP was improved by
approximately 30%. This study demonstrated different colloidal processing stages and proved that high colloidal stability
and fine particle size are vital to produce highly translucent Y-TZP.